Apparatus and method for allowing and interrupting the flow of thermoplastic materials



me 4, 1953 J. L. MCCURDY ETAL. PPRTUS ARD HETHOD FR LLOWING AKDIRTERRUTING TEE TLO OF THEPJOPLSTIC MATERIALS Filed liay 27. 1966 me KlE st N .sk

Rohff Wallen United States Parent Glce 3,386,495 Patented June 4, 1968ABSTRACT 0F THE DISCLOSURE A shaped means spanning an opening, thcshaped means being a conduit having reverse loops` for transporting aheat exchange medium baci; and forth across the opening, the openinghaving a periphery defining it for passing heat sensitive materialstherethrough, and retaining means for holding the shaped conduit meansso that the heat exchange medium may be circulated to rcgulate the llowof the heat sensitive materials passing through the opening novelapparatus for allowing, interrupting, and rcgulatiug the ow of heatsensitive materials can be utilized wherever an opening dened by aperipheral means for moving materials therethrough exists, such aspipelines, manifolds, storage tanks, ctc.

This invention relates to novel method and apparatus for retaining -andallomng the movement of thermoplastic materials. 'l'nc inventionparticularly relates to vessels arid lines, such as thcrmop'zasticholding tanks :uid pipelines which have as an inherent part or as anadditional part therein an apparatus which uniquely provides for theflow and cessation of flow of tiiermoplastics. The new method andapparatus to be described herein is applicable to other adaptations,such a in pipeline manifolds or many types o vessels to interrupt,regulate and permit the tow of materials which have viscositycharacteristics that are responsive to heat.

Marty types of devices and methods are shown in the art for providingopening and closing means to hold ma terials in tanks, lines, and othertypes of vessels. These holding devices cover a broad range ofpneumatically, hydraulically, and mozhanically actuated valves; however,it is believed that none of the prior art discloses the novel subjectmatter described and claimed herein. In the various segments of theprior art concerning the handling of materials which havecharacteristics wherein viscosity is responsive to heat, the existingmaterial holding devices, vessels and lines have limited etlectivenessand disadvantages due to the absence of simple means lor allowing andinterrupting the .flow o the highly viscous thermoplastic materials.This is panicularly true where valves and other types of closures havemoving parts which come directly into contact with the plastic material.Often, the substances handled are of such a highly viscous nature intheir owahle state that substantially large openings are required.Furthermore, when mechanical and other types of valves are used to closelarge openings, the metallic mass of the valve retails heat whichdestroys the desirable uniform rate of heat transfer within the materialnext to the valve and adversely allects that material. Also, thematerials are frequently of such a nature, and the processingrequirements such that it is imperative to move the substances asquickly as possible or to positively retain them in a manner unavailableprior to this invention. Furthermore` holding vessels can be constructedin accordance with this imention so that should vessel withdravctlapparatuses, such as pumps, and auger-type con` veyors, break down ormalfunction, the movement of material can be interrupted inmediatelyupstream from the equipment problem andv the apparatus repair can becarried out without removing the entire contents of the vessel.

This invention also provides a novel method and ap. prratus foroomrencing and interrupting the flow of marials in pipelines andpipeline systems wherein one or more of these novel devices can beinstalled within a. pipeline near a juncture or im a manifold system tostart and stop the Sow of plastic materials and to direct the .flow ofsaid materials along the desired paths.

It is a primary ohiect of this invention to provide a. vessel having anovel rigid meas-.s and method for allowing and interrupting the tios-ro thermoplastic materials wherein no moving parts are involved.

It is a further o'nject of this "xvention to provide appezams and methodfor stopping and starting the riow of thermoplastic materials from avessel wherein the cessation of ow is such that the withdrawal means maybe removed from the loner suction ports of the vessel order tofacilitate the rapid repair of equipment without removing the contentsof saidl vcsseL Imolher obiect of this invention is to provide novelmeans and method for commencing and. stopping the flow of thermoplasticmaterials in. pipelines.

A further object of this invention is to provide novel means and methodfor changing the path of ow of thermoplastic materials at pipelineiunctures and in pipcline manifolds.

lt has been discovered that a heat exchange apparatus such as a shapedmeans for passing a heat exchange mediuzn therethrough may be placed ordisposed within the cpe-ning of a vessel through which the thermoplasticcontents of said vessel must pass so that as the materid passes over andbetween the surfaces of said heat exchange apparatus heat may hewithdrawn from said materials to stop said flow orthe temperature mayremain constant or heat can be applied to said materials to cause ilow.or to continue the fion' of said thermoplastic materials. The shapedmeans for transporting a heat exchange medium may be inserted in apipeline in a direction transverse to the flow of materials within saidline so that thermoplastic materials may dow over and between saidsurfaces without substantially reducing the open cross sectional area ofsaid line and without creatine signilicant obstructions to flow. Heatcan he remos' fromk the material flowing over the smooth surfaces of theheat exchange apparatus by introducing a cold heat exchange medium intothe conduit-like heat exchange apparatus to remove heat from saidflowing material to cause seid material to become substantially solid :ointerrupt the flow of the material without the aid of naming pans.Conversely, when a heated heat exchange medium vis introduced into theapparatus. the substantially sad thermoplastic matcn'al upon taking upher-.t becomes les viscous and dow mITICRCCS.

The accompanying drawings illustrate the preferred embodiments of thisinvention; however. it is understood that the specific details ot thesystem may vary widely without departing from the basic principles ofthe invention wherein:

FIG. l is :iii elevation vieu' of a holding tank;

FIG. 2 is a sectional view of the plastic valve taken at lines 2-2 inFIG. l; and

FIG. 3 portrays the plastic valve adapted for use in a. series ofpipelines Referring to FIG. 1, tank may be any type of vessel forholding thermoplastic material; which for the purpose o of illustrationhas an opening Il' at the topiI 13 equipped :da material introductionmeans 14 to which material is mpplied from lia: 1S. Vessel Il isequipped at its lower portion 16 with an opening I7 forth: removal ofthe contained thermoplastic materials. Lower portion 16 of vessel 11 isequipped with a periphery 18 defining opening 17, said periphery havingjoined thereon a retaining meam 19 for holding the novel plastic valveassembly 20. lm- 5 rnediatcly belov: valve mscmbly 2G and joined to thelower extremity of tank 11 is withdrawal means 21 which may be a geartsm or auger type pump forfacilitating the removal oi' the contents ofvessel 11 through line 22.

FIG. 2 taken at lines 2 2 in PIG. l is a view of the m plastic valveassembly wherein retainer 19 is shown holding the heat exchangeapparatus 23 having inlet 24 and outlc lor the Circulation of a heatexchange rnedium in a path through said exchange meansldcned by theconfiguration oi' said means as it passestacross the 15 opening dcriedby vessel periphery 1S.

FIG. 3 Ais a pian vicv.' oi a pipeline junction 26 wherein lines 27, 2S,29. and 30 each being equipped with the novel plastic valve 31. Heatexchange apparatus 23 in plastic valve 31 crosses the interior of eachpipe in a di- 2Q rection transverse to the ow of thermoplastic materialand the reversing loops 23a in the heat exchange apparatus are locatedon the exterior of each pipe within the insulated periphery 32 of theplastic valve 31. Each plastic valve 3l in lines 27, 28, 29, and 30 isequipped with 25 inlet and outlet means 24 and 2S, respectively, shownin FIG. 2 for the introduction and removal of a heat exchange medium.

ln operation the plastic valve assembly 20` shown in FIG. 2 is placedwithin a section or opening in a vessel 30 or line in a directiontransverse to the flow of material. The plastic valve assembly may be aseparate unit mounted on a lienge or periphery for insertion into avessel or a pipeline at any desired point, or the plastic valve assemblymay 'oe built into the vessel or line and held in 35 place by welding oras an inherent part of the vessel or the line. The shape of the heatexchange apparatus 23 may have any conguration, preferably' one thatminimizes obstructions across the cross sectional area of a line or inthc opening of a vessel from which the contents are withdrawn orintroduced. To minimize tlm space occupied by the heat excmnge apparatus23 reverx loops 32a can extend through the periphery 18 or the reversed`loops can be built into said periphery so that said loops are locatedoutside the opening through which the materials pass. Certainly, forspecic purposes or for particular adapta- 4 rions the reverse loops 23ain the heat exchange appara. tus. which is a part of the plastic valveassembly 20, can also be located entirely within the openings.

Since the material moving across the smooth surfaces of the heatexchange apparatus 23 has heat sensitive viscosity characteristics, whena heated medium is introduced into the heat exchange apparatus at inlet24 and follows a particular path through said apparatus and said reverseloops 23a denne. by any desired special oonliguration of the valveassembly 20, heat is trami'erred to the matcn'al, thereby reducing theviscosity or resistance to ow of said material and consequentlypromoting the flow of the materials as the heated medium is drculatedthrough the conduit-like heat exchange apparatus to the outlet 25.Conversely, when the heat exchange medium introduced into apparatus 23at inlet 24 for circulation through said apparatus and subsequentremoval at outlet 2S is cool in comparison to the thermoplastic materialmoving over the smooth exterior surfaces of the apparatus, the mate- 5rial becomes more viscous and substantially solid to form a plug-likemass "hiel: has the oongruation of the interior ot' the vessel or line,and the ow of saidmaterial is interrupted. l

In FIG. l, as thermoplastic materials previously intro- 70 duced intovessel 11 through opening 12 at top 13 by introduction means 14 iswithdrawn from said vessel over the smooth surfaces of heat exchangeapparatus 23 at the lower vessel portion 16 through the periphery 18delining opening 17 by withdrawal means 2L A heated circs!` 75 latoryheat exchange medium is moved through the heat exchange apparatusdisposed across opening 17 to facilitate the flow of said thermoplasticmaterials. However, should it be desired that flow of thermopluticmaterials from vessel 1l over the smooth surfaces of heat exchange means23 in opening 17 be interrupted, the passage o.' a cool circulatory heatexchange medium through heat exchange means 13 of assembly 20, shown inFIG. 2, is provided so thatr heat is transferred from thc exudingthermoplastic materials to cause said rnate` rials to become a plug-likenon-{iowable substantially solid mass about the conduitdilcc heatexchange apparatus. In the FIG. l embodiment this method is particularlyadvantageous when the breakdown of withdrawal equipment 2t, such as gearor auger type pumps located immcdiately outside the lower portion 16 ofvessel 11, become inoperative and require immediate repair, because theflow of material from vessel 11 can be simply and uniquely interruptedat the opening immediately above said equipment.

This method and apparatus provides a way of circumventing the necessity'ot removing the remaining contents ci the vessel and the instantinvention also provides rapid access to the maliunctioning equipment.Prior to the con. ception of this novel means and method forinterrupting and commencing the flow of thermoplastic materials, whenwithdrawal apparatus became inoperative it was necessary to drain thethermoplastic materials from the vessel before repairs could be made.The drained material was discarded at substantial expense in time,labor, and product loss. An alternative was to cool the entire tank ofthermoplastic materials which required about three to four days prior toapparatus repair, followed by the reheating of the system which requiredan additional fourday period. This plastic valve assembly being entirelyfree of moving parts limits mechanical and other types of wear andconsequent maintenance since only the in. troduetion and removal of acirculatory heat exchange medium, which is generally readily availablein thermoplastic producing installations, provides the commence ment andinterruption of flow.

The circulatory heat exchange medium can be hot oil which is circulatedfrom the central reactor system. For polystyrene or polyelhylenes, thehot oil circulated through the heat exchange apparatus can have atemperazure within the range of 400-500 F., preferably 425- 4 75 F., topermit the llow of the thermoplastic matenals. For polyvinyl chloridesthe hot .oil temperatures een bc within the range of 20D-300 F.,preferably 23S- 270 F., to permit the liow of said PVC thermoplasticmaterials. To interrupt the ow of the thermoplastic materials the sameoil heat exchange medium can be circu lated through the conduiblike heatexchange apparatus and this oil can have a temperature within the rangeof about 40-l00 F., or more, depending upon outside tcmperatureconditions since the oil will probably be at atmospheric temperature.Water can be used as a circulatory hear exchange medium; however, athigher ternperatures a high pressure system is required and signin. cant water treatment is necessary to prevent precipitation of solids fromthe water throughout the heat cx change equipment installation.

ln the operation of the embodiment shown in FIG. 2, thermoplasticmaterials introduced into line 27 may be stopped at the plastic valve 3llocated at position 27a when a cool exchange medium is introducedthrough the shaped conduit mcansof the heat exchange apparatus 23 towithdraw heat from the flowing material. Commence ment of flow of saidmaterial beyond position 27a is provided by the introduction andcirculation of a heated circulatory medium within heat exchangeapparatus 23. Subsequently, the tlowingmatcrial may be routed in anyandall directions through lines 28, 29, and 30 by the introduction of aheated or cooled circulatory medium through the heat exchange means 23located in plastic valve 31 at valve positions 27a, 23S. 290. md 3542Furthermore. all plasti: valves may be turned on or "turned oil" by theintroduction ot' a heated or cooled medium in accordance with theteachings of this specication simultaneously or alternately, dependingupon the requirements inany specific situation. Similarly, a systern ofplastic valves may be used in a complex manifold in the directing andtransporting of heat sensitive thermoplastic materials.

Additional advantages provided by this novel apparatus and method forcommencing.. interrupting, and directing the ow of thermoplasticmaterials reside in the ability to aurately control the heat transfer inthe system, that is, the amount of heat introduced into thethermoplastic mediumor withdrawn therefrom may be controlled quiteaccurately by the temmrature of the circulatory heat exchange mediumpassing through heat exchange means 23. in contrast where a largemassive valve type mechanical closure means is used to interrupt the iowof materials, these massive plugs, gates, etc., which are generallyconstructed of metal, create leakage problems and the asbestos orgraphite impregnated asbestos valve packing can contaminate thethermoplastic materials. Additionally, the massive metal plugs or gatesretain heat which delcteriousiy ctiect the thermoplastic material in azone around these obstructions since the heat transfer cannot beadequately controlled. Furthermore, the above problems and many othersare avoided in the operation of the disclosed apparatus and theapplication of the described methods in a system free of moving parts asdiscussed herein.

While in the foregoing specification this invention has been describedin relation to preferred embodiments thereof, and many details have beenset forth for the pur pose of illustration, it will be apparent to thoseskilled in the art that the invention is susceptible to other emboziiments and that many of the details set forth herein can be variedconsiderably without departing from the basic principles of theinvention.

Having thus described the invention. what is claimed is:

l. Apparatus for allowing and interrupting the flow of thermoplasticmaterial including in combination:

(a) a shaped means for transporting a heat exchange medium across anope..ing through which thermoplastic materials ow;

(h) peripheral means defining said opening; and

(c) retaining means located adjacent said peripheral means for holdingsaid shaped means.

2. The structure of claim I wherein said shaped means is a conduithaving reverse loops and passing across said opening at spacedintervals.

3. The structure of claim 2 wherein said conduit means has an inlet andan outlet for continuously circulating :aid heat exchange medium.

4. A vessel for holding thermoplastic material including in combination:

(a) a peripheral means defining an opening for with drawing thethermoplastic material'contained therein;

(b) a shaped means for transporting a heat exchange medium at intervalsacross said opening through which thermoplfotic materials flow; and

(c) retaining means located adjacent said peripheral means for holdingsaid shaped means.

5. The structure of claim 4 wherein said shaped means is a conduithaving reverse loops and extending at inten-als acre A said opening.

6. The structure of claim 5 wherein said con-duit has inlet and outletmeans for contrzuousy circulating said heat exchange medium.

7. A pipeline system for transporting a thernmplastic material and forallowing, irttertrtrptin;` and directing the ow ot said material,said-system travi-ig in combination:

(al a junction wherein at least. two nes cross:

(b) cach line equipped with a shaped means for traesporting a heatexchange rneiurn at intervals across the interior of said line. saidshaped means located a distan-:e from said iur-:tion: ani

(c) retaining means located adjacent said peripheral means [or hol-.tingsaid shaped means- 8. The structure of claim 7 wherein sai-.l functionis located in a pipeline anifold;

9. The structure ot' claim 7 wherein said shaped means is a conduithaving reverse loops and extending across the interior of said line atintervas.

10. The structure of claim 9 wherein seid shaped means include an inletand an outlet for circulating :t heat exchange medium.

1l. The structure of claim 7 wherein said retaining means is aninsulated exterior ring.

12. ln a process for allowing and interrupting the flow of thermoplasticmaterials in a "es'el, the steps of Iiowing thermoplastic materialsthrough an opening and across the smooth sufaces of a heat exchangeapparatus, passing a cool heat exchange merum through the exchangeapparatus over which thermoplastic materials flow to remove heat fromsaid materials to cause said materials to become substantially solid tointerrupt said flow; and circulating a heated medium through seid heatexchange apparatus over which thermoplastic materials ew to heat saidmaterials to decrease viscosity of said mtet'ials to cause flow.

13. The process ot' claim I2 wherein the allowance and interruption offiow oi thermoplastic materials is in a pipeline system.

14. The process oi' claim 13 wherein the a lowartce and interruption ofthe flow of thermoplastic materials is in a thermoplastic holding tank.

15. The process of claim 12 wherein the cool heat ex change medium has atemperature within the range of 40-100 F. or more.

16. The process of claim l2 wherein :he heated mediurn has a temperaturewithin the rarge of 40S-50G' F preferably 425-475 F.

17. The process of claim 12 wherein tthedzeated medium has a temperaturewithin the range of X50-SUG' F., prefcrably 23.i270 F.

18. The process of claim I2 wherein the thermoplastic materials arepolystyrenes.

t9. The process ot' claim l2 wherein the thermoplastic materials arepolyvinyl chlorides.

20. The process of claim I2 wherein the thermoplastic materials arepolyethylenes.

References Cited. UNITED STATES PATENTS ROBERT A. O'LEARY, Primary Emmr,CHARLES SUKALO. Examiner.

